1. Physics 564 – Particle Physics Matthew Jones - Phys 378 Office hours: after class or by appointment Web page: http://www.physics.purdue.edu/~mjones/phys564 Should contain: –Course outline, nominal schedule –Lecture notes –Assignments –Supplementary material (long derivations) –Computing instructions and examples

2. Other information Particle Data Group: http://pdg.lbl.govhttp://pdg.lbl.gov –order your free copy today.order your free copy today. Text: Halzen & Martin –Provides most of the theoretical background –Not out of date, but by now it is incomplete Other texts: –Perkins, Griffiths, Aitchison & Hey, Leader & Predazzi, Bjorken & Drell, de Wit & Smith, … Historical development: –The Rise of the Standard Model, Hoddeson, et al. (ed.) –Constructing Quarks, Pickering

3. Other information Grading: 70% assignments, 30% final project Assignments: –Plan for about 6 assignments –Some computing component to assignments –Free to use any platform/software you want –Examples using ROOT will be provided on web the pageROOT –Everyone should have an account with PCN –First exercise will be to make sure that this really works as advertised

4. Relation to other subjects Quantum Field Theory, String Theory –eg. Quantum Field Theory, Ryder, Itzekson & Zuber Detector Instrumentation –eg. Introduction to Experimental Particle Physics, Fernow Accelerator Physics –eg. An Introduction to Particle Accelerators, Wilson Nuclear Physics –eg. Introductory Nuclear Physics, Krane Astrophysics, Cosmology Course dedicated to Standard Model and its extensions, eg. Phys 565.

5. Pre-Modern Particle Physics Particle concept is not new: –Central forces, action at a distance (Newton) –Kinetic theory of gases (Bernoulli, 1738) –Boscovich: gasses composed of massive, point like particles with central forces –No quantum mechanics but otherwise similar to the way we think of particle physics –Forces turn out to be a consequence of the exchange of “virtual quanta”

6. “Modern” Physics The first particle accelerator?

7. “Modern” Physics X-rays (Roentgen, 1895) Electron (Thompson, 1897) – measured Q/m Radioactivity (Becquerel, 1900) Atomic model (Rutherford, 1911) Cosmic Rays (Hess, 1912) Proton (1919) Neutron (1931) Nuclear Physics

8. Quantum Mechanics Particle nature of x-rays (Compton, 1924) Wave nature of matter (de Brogle, 1925) Wave mechanics (Schrodenger, 1926) Relativistic Quantum Mechanics (Dirac, 1928) Particle accelerators: –Particles emitted in nuclear decays –Cosmic rays (Hess, 1912) –Ray transformer (Wideroe, 1928) –Electrostatic (Cockcroft Walton, 1932-34) –Cyclotron (Lawrence, 1930) –Betatrons, synchrotrons (1940’s)

11. Particle Detectors Charged particles will ionize the material through which they move. The ions produce chemical or physical changes in the material. –Photographic emulsion –Cloud chamber –Bubble chamber –Spark chamber –Modern electronic tracking detectors

12. Particle Detectors Emulsion: Cloud Chamber: Incident cosmic ray Target nucleus Lots of particles (mostly pions)

13. Particle Detectors Bubble Chambers –Used in fixed target experiments at particle accelerators –The detector material is the target –Filled with liquid H 2, D 2, freon, etc… –Pressure keeps it in a liquid state –Charged particles ionize it –Sudden reduction in pressure produces bubbles along the ionized paths

14. Bubble Chambers

15. Modern Particle Detectors Still only detect charged particles Indirectly sensitive to neutral particles: –eg.   e + e -, np  pp  - Can be triggered: –Electronic signals recorded only when something “interesting” happens Data written to mass storage medium Analyzed “offline”

16. Modern Particle Detectors ALEPH detector:

17. Modern Particle Detectors ALEPH detector:

18. Other Particle Detectors

19. Particles

20. Particle Physics What are their properties? –Mass and charge –Spin and magnetic moment –Internal quantum numbers: C, P, “Isospin” –Lifetime –Branching fractions The Particle Data Group compiles the Review of Particle Properties…Particle Data Group

21. Example:

22. Phenomenology Which particles are truly elementary? Do we understand why particles have their observed properties? What can we calculate? Are the calculations reliable? Can we compare them with experiment? Is there an underlying theory that explains everything?

23. Phenomenology Particles that don’t interact are described by quantum mechanics and special relativity Interactions are described by –Empirical parameterizations –Dynamical models

24. Particle Interactions (Forces) Particles interact by the exchange of virtual quanta Only know of four forces: –Electromagnetism –Weak nuclear force –Strong nuclear force –Gravity Each is associated with a class of particles –eg. Electromagnetism  photon “Electroweak”

25. Particle Interactions If we know how a particle couples to a particular force carrier then we can calculate probabilities: What is harder is doing the reverse… –Measure probabilities –Deduce the form of the Hamiltonian, H That is essentially what Particle Physics is about.

26. Unanswered Questions What are the most fundamental types of matter? Are there only four forces? Is the model that describes them self-consistent? Why does nature look this way? Are there cosmological implications? We think we might get some answers in the next decade…